As shown in FIG. 1, a prior art bicycle parking frame comprises mainly a plate 11 and a support rod 12. Such a bicycle parking frame as described above is intended to support the bicycle on the ground in a slightly tilting manner. The plate 11 is fastened securely with the bicycle frame. The support rod 12 is fastened with the plate 11 such that the support rod 12 can be caused to swivel so as to support the parked bicycle in a slightly tilting manner. The optimum inclination, at which the bicycle is parked, ranges between 6 and 12 degrees. In other words, a bicycle which is parked at the inclination smaller than 6 degrees or greater than 12 degrees is vulnerable to toppling.
It is necessary to provide a bicycle with a parking frame of an appropriate size in accordance with the size of the bicycle frame. There are bicycle frames of various sizes. Accordingly, the bicycle parking frames of various sizes must be made. Such a manufacturing practice of making the bicycle parking frames of various sizes is not cost-effective. In addition, the prior art bicycle parking frames are defective in design in that they do not allow a bicyclist to adjust at will the inclination at which the bicycle is parked.
With a view to overcoming the drawbacks of the prior art bicycle parking frames described above, a variety of new and improved bicycle parking frames were disclosed. The known bicycle parking frames are adjustable in length; nevertheless they are rather complicated in construction and can not be made economically.